An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

Of a gas or plasma, the temperature deduced from the → populations of atomic → excited states, as expressed by the Boltzmann formula: N_u/N_l = (g_u/g_l) exp (-ΔE/kT_ex), where N_u and N_l are the upper level and lower level populations respectively, g_u and g_l the statistical weights, ΔE = hν the energy difference between the states, k is → Boltzmann's constant, and h→ Planck's constant. The higher the energy of the occupied states, the higher the excitation temperature.

→ excitation; → temperature.

Relating to or characteristic of a unified body (e.g. a government) with constituent parts (states) that retain a measure of autonomy.

From Fr. fédéral, from L. foedus (genitive foederis) "league, treaty, alliance," → federate, + → -al.

Hiyâvi, from hiyâvidan, → federate.

1) To join together in a → federation.
2) To organize on a → federal basis.

From L. foederatus "leagued together, allied," p.p. of foederare "to establish by treaty," from foedus "league, treaty, alliance," related to fides "faith."

Hiyâvidan, from Tabari hiyâ "together, with each other," probably related to Av. hi- "to chain, bind," hiθav- "association, assemblage," hinav- "bond, chain," hita- "fastened;" O.P. vištāspa- literally "with unbound horses;" Av. hitāspa-; Pers. gošudan "to open," → resolve; cf. Skt. sā-/say- "to bind, fasten, fetter." Coined on the model of Ger. Bund "federation, alliance, band," cognate with Pers. bastan "to bind," → absolute.

A composition of different databases which work in an integrated manner while preserving their autonomy.

→ federate; → database; → system.

1) The act of federating or uniting in a league.
2) A political unit formed from smaller units on a → federal basis.

Verbal noun of → federate.

Pertaining to or of the nature of a → federation.

→ federate.

He who, or that which, federates.

Agent noun of → federate + → -or.

An old explanation, proposed by Enrico Fermi, of the → weak interaction.

→ fermi; → interaction.

An operator defined as: ▫ = (∂/∂x, ∂/∂y, ∂/∂z, 1/(jc∂/∂t).

→ four; → dimensional; → operator.

The portion of the 4π → steradians of the sky that a radiotelescope can observe from a given location on Earth over a 24-hour time interval.

→ fractional; → sky; → coverage.

Any of the four interactions in nature between bodies of matter and that are mediated by one or more particles. Also called the → fundamental force. In order of decreasing strength, the four fundamental interactions are the → strong interaction, the → electromagnetic interaction, the → weak interaction, and the → gravitational interaction.

→ fundamental; → interaction.

(Adj.) 1) Not limited to one class, field, product, service, etc. 2) Relating to the whole or to the all or most. 3) Dealing with overall characteristics, universal aspects, or important elements.
See also:
→ general precession, → general relativity, → generalization, → generalize, → generalized, → generalized coordinates, → generalized forces, → generalized momenta, → generalized velocities, → New General Catalogue (NGC).

From L. generalis "relating to all, of a whole class," from genus "race, stock, kind," akin to Pers. zâdan, Av. zan- "to bear, give birth to a child, be born," infinitive zazāite, zāta- "born;" Mod.Pers. zâdan, present stem zā- "to bring forth, give birth" (Mid.Pers. zâtan; cf. Skt. jan- "to produce, create; to be born," janati "begets, bears;" Gk. gignomai "to happen, become, be born;" L. gignere "to beget;" PIE base *gen- "to give birth, beget."

Harvin, from Mid.Pers. harvin "all," from har(v) "all, each, every" (Mod.Pers. har "every, all, each, any"); O.Pers. haruva- "whole, all together;" Av. hauruua- "whole, at all, undamaged;" cf. Skt. sárva- "whole, all, every, undivided;" Gk. holos "whole, complete;" L. salvus "whole, safe, healthy," sollus "whole, entire, unbroken;" PIE base *sol- "whole."

The secular motions of the → celestial equator and → ecliptic. In other words, the sum of → lunisolar precession, → planetary precession, and → geodesic precession.

→ general; → precession

The secular displacement of the → equinox on the → ecliptic of date.

→ general; → precession; → longitude.

The secular motion of the → equinox along the → celestial equator.

→ general; → precession; → right ascension.

Of, relating to, or subject to the theory of → general relativity.

→ general; → relativistic.

The theory of → gravitation developed by Albert Einstein (1916) that describes the gravitation as the → space-time curvature caused by the presence of matter or energy. Mass creates a → gravitational field which distorts the space and changes the flow of time. In other words, mass causes a deviation of the → metric of space-time continuum from that of the "flat" space-time structure described by the → Euclidean geometry and treated in → special relativity. General relativity developed from the → principle of equivalence between gravitational and inertial forces. According to general relativity, photons follow a curved path in a gravitational field. This prediction was confirmed by the measurements of star positions near the solar limb during the total eclipse of 1919. The same effect is seen in the delay of radio signals coming from distant space probes when grazing the Sun's surface. Moreover, the space curvature caused by the Sun makes the → perihelion of Mercury's orbit advance by 43'' per century more than that predicted by Newton's theory of gravitation. The → perihelion advance can reach several degrees per year for → binary pulsar orbits. Another effect predicted by general relativity is the → gravitational reddening. This effect is verified in the → redshift of spectral lines in the solar spectrum and, even more obviously, in → white dwarfs. Other predictions of the theory include → gravitational lensing, → gravitational waves, and the invariance of Newton's → gravitational constant.

→ general; → relativity.

→ secretary-general.

→ general; → secretary.

The act or process of generalizing; → generalize.
A result of this process; a general statement, proposition, or principle.

Verbal noun of → generalize.

To make general, to include under a general term; to reduce to a general form.
To infer or form a general principle, opinion, conclusion, etc. from only a few facts, examples, or the like.

→ general; → -ize.